Wolfson Microelectronics has introduced a high input voltage ADC with an extended clocking scheme, to interface to a wider range of host processors. The WM8781 complements the existing WM8782, which was a ADC to accept 2Vrms analogue input signals directly. The device offers a stereo, high performance audio ADC solution for recordable media applications such as DVD players, Personal Video Recorders, Set-Top Boxes and studio audio processing equipment. The ADC sampling frequency is up to 192kHz. The device offers the additional capability of a 384fs Master mode, for host processors generating this clock frequency, as well as supporting Master or Slave mode clocking schemes.

Stereo line level inputs in the WM8781, along with two control input pins, allow operation of the audio interface in three industry standard modes; I2S, RJ and LJ. An internal op-amp is integrated on the front end of the chip to accommodate analogue input signals greater than 1Vrms. A stereo 24-bit multi-bit sigma-delta ADC is used with 128x, 64x or 32x over-sampling, according to sample rate. Digital audio output word lengths from 16-24 bits and sampling rates from 8kHz to 192kHz are supported. The device also has a high pass filter to remove residual DC offsets. The WM8781 is available now in a 20-pin SSOP package.